There has been proposed a laser printer having a developing device wherein a toner box for housing a toner is attachable to and detachable from the developing device (see, for example, JP-A-7-225514).
JP-A-7-225514 discloses a developing device including a toner box and a case. The toner box includes a toner outlet for discharging toner, and a first shutter for closing the toner outlet. The case of the developing device includes a toner inlet for receiving the toner discharged from the toner outlet, and a second shutter for closing the toner inlet. In the toner box, a sealing material is interposed between the toner box and the first shutter, and around the toner outlet. In the case, a sealing material is interposed between the case and the second shutter, and around the toner inlet.